Since the day they met at Yale in 1962 as architecture students, their paths have followed similar trajectories. Though their initial partnership, Team 4, ended in 1967, they have moved in tandem, rising to become pre-eminent modernist designers. They both have headquarters in London overlooking the Thames. Now Lord Rogers of Riverside and Lord Foster of Thames Bank have another tie that binds. They have designed skyscrapers that will stand side by side in the most closely watched slice of real estate in the world: Ground Zero.

For the past four months, teams from the two men's practices have been hidden away in an office overlooking the World Trade Centre site, creating the initial designs for two of the four skyscrapers that will replace the fallen Twin Towers of September 11.

Working alongside a team from the Japanese firm of Fumihiko Maki, they have created plans that are indisputably in their own style, yet complementary and reflective of the calamity of 9/11.

At the unveiling of the designs yesterday, ahead of Monday's fifth anniversary of the New York attacks, Lord Foster said the cluster of buildings would symbolise "the renaissance of the New York skyline. It is about looking forwards, but also respecting and honouring the past."

The three new towers are the final pieces in the World Trade Centre jigsaw. After years of wrangling, delays and politicking, the full picture of the reconstructed site is now clear. It broadly conforms to the masterplan laid down by Daniel Libeskind, the Polish-born American architect.

His plan centred on tower 1, which he dubbed the Freedom Tower, and which has been designed by David Childs, the architect working on behalf of the property developer of the site, Larry Silverstein. Under Libeskind's conception, the Freedom will taper to a symbolic 1,776 feet (541.3 metres), making it taller than any existing building. The three newly designed towers will cascade from that, in a gradually declining spiral.

First after the Freedom Tower will be the Foster building, revealed yesterday. It is in itself a cluster of four towers, rising to 1,254ft, 78 floors high and each capped with a sharp point. Illuminated at night, these peaks will shine for miles as four brilliant diamonds.

Slightly shorter at 1,155ft, with 71 storeys, will be the Rogers building. It does not place the services on the outside - his trademark since his 1971 design with Renzo Piano of the Paris Pompidou Centre. But it does have an outer skeleton of steel bars and four rooftop antennae that give the design a spikiness that plays well against the smooth confidence of the Foster tower. "We believe that we have designed a transparent and legible building," Lord Rogers said.

Maki's is the third and smallest, at 947ft. It is also the quietest. "We wanted an abstract and minimalist approach," said Maki. It follows the sweep of the four towers and twists to face the Freedom Tower.

The voices of three such high-profile designers could easily have clashed. But yesterday's presentation suggested they act more as a chorus. There are shared themes at work. Most prosaically, all the towers have been conceived so their corners are glazed and open, offering spectacular views across lower Manhattan.

Less visible was the question of security. With the collapse of the twin towers in their minds, the architects have created more resilient buildings. That explains the external lattice on the Rogers tower: it is a load-bearing structure that means if a column was destroyed through a bomb or other catastrophe it would still stand. The Foster building is constructed around a solid concrete core, so there is no chance of the structure melting and falling as did the twin towers. And the Maki tower has double columns throughout.

The towers all pay homage to the 9/11 memorial that dominates the site: two reflective pools of water that occupy the exact footprint of the twin towers.

At night the diamonds at the top of the Foster building will lead the eye down to the memorial pools. "The crystalline top of the tower bows down to the memorial park commemorating the tragic events that unfolded here," said Lord Foster. "But it is also a powerful symbol of hope for the future."

The tower has also been placed along an axis so one side will be lit up by a ray of sunshine in the morning that on September 11 will fall at precisely 8.46am - the moment the first plane hit.

Paul Goldberger, who has written the definitive book on the rebuilding of the World Trade Centre, Up from Zero, said he was pleasantly surprised by some aspects of the new designs. Libeskind's spiralling cascade had been retained, and the three new towers were more harmonious than he had feared.

But he added: "I do feel that all three of the new buildings are better unto themselves than as an ensemble. They are not designed to respond to each other."